Compressor vanes in aero gas turbine engines are typically manufactured from aluminum, steel, nickel allows, or from carbon fiber composites. The airfoil shapes of such vanes have to date, however, remained relatively simple in order to enable the vanes to be manufactured from relatively simple metal forming methods. Aerodynamic performance improvements have led to more complex shapes especially on the leading edges (LE) of vanes, which results in metal vanes that must be machined from solid bars.
Increasing demands for lower weight products in aero gas turbine engines have seen an increasing use of carbon fibre composite products, especially vanes. FOD (foreign object damage) resistance, including resistance to ice projectiles for example, and erosion resistance for carbon composite vanes is often achieved by using a metal sheath that is bonded onto the leading edge (LE) of the composite vane. When the vane LE shape is relatively simple, the manufacture and application of the metal sheath is straightforward. However, when the LE is a complex shape, the metal sheath is required to be manufactured from alternative methods such as hydroforming and this results in higher cost.
Furthermore, complex aerodynamic vane shapes often have to be compromised for reasons of vane dynamics, resulting in reduced engine performance and increased specific fuel consumption.
Accordingly, improved vanes and vane assemblies which offer, for example, the ability to form complex airfoil shapes having uncompromised aerodynamic characteristics and satisfactory vane dynamic characteristics, while remaining lightweight yet sufficiently resistant to erosion and/or FOD and which can be readily manufactured at low cost, are desirable.